Ai giúp mik bài này mik cho 1000000 tick ^_^"
Tính : A = 1.4 + 2.5 + 3.6 +...+ 99.102
tính A=1.4+2.5+3.6+...+99.102
A = 1.4 + 2.5 + 3.6 + ... + 99.102
A = 1.(2 + 2) + 2.(3 + 2) + 3.(4 + 2) + ... + 99.(100 + 2)
A = (1.2 + 2.3 + 3.4 + ... + 99.100) + (1.2 + 2.2 + 3.2 + ... + 99.2)
Đặt B = 1.2 + 2.3 + 3.4 + ... + 99.100
3B = 1.2.(3-0) + 2.3.(4-1) + 3.4.(5-2) + ... + 99.100.(101-98)
3B = 1.2.3 - 0.1.2 + 2.3.4 - 1.2.3 + 3.4.5 - 2.3.4 + ... + 99.100.101 - 98.99.100
3B = 99.100.101
B = 33.100.101 = 333300
A = 333300 + 2.(1 + 2 + 3 + ... + 99)
A = 333300 + 2.(1 + 99).99:2
A = 333300 + 100.99
A = 333300 + 9900
A = 343200
Tính A = 1.4 + 2.5 + 3.6 +...+ 99.102
A = 1.4 + 2.5 + 3.6 +...+ 99.102
A = 1(2+2)+2(3+2)+3(4+2)+.+99(100+2)
A = 1.2+1.2+2.3+2.2+3.4+3.2+.+99.100+99.2
A = (1.2+2.3+3.4+.+99.100)+2(1+2+3+.+99)
tính:
A=1.4+2.5+3.6+...+99.102
A = 1(2+2)+2(3+2)+3(4+2)+...+99(100+2)
A = 1.2+1.2+2.3+2.2+3.4+3.2+...+99.100+99.2
A = (1.2+2.3+3.4+...+99.100)+2(1+2+3+...+99)
A = 333300 + 9900 = 343200
CHÚC BẠN HỌC TỐT ^-^
=(102 - 1) +1 :3
= 34
(bạn lấy số cuối trừ số đầu cộng 1 chia khoảng cách là 3)
Cái này là toán lp 6 nha bn
A = 1.4 + 2.5 + 3.6 + ... + 99.102
A = 1.(2+2) + 2.(2+3) + 3.(2+4) + ... + 99.(2+100)
A = 1.2 + 1.2 + 2.2 + 2.3 + 3.2 + 3.4 + ... + 99.2 + 99.100
A = (1.2 + 2.2 + 3.2 + ... + 99.2) + (1.2 + 2.3 + 3.4 + ... + 99.100)
A = 2.(1 + 2 + 3 + ... + 99) + 1/3.[1.2.(3-0) + 2.3.(4-1) + 3.4.(5-2) + ... + 99.100.(101-98)]
A = 2.(1 + 99).99:2 + 1/3.(1.2.3 - 0.1.2 + 2.3.4 - 1.2.3 + 3.4.5 - 2.3.4 + ... + 99.100.101 - 98.99.100)
A = 100.99 + 1/3.99.100.101
A = 9900 + 33.100.101
A = 9900 + 333300
A = 343200
Ủng hộ mk nha ^_-
tính:
A=1.3+2.4+3.5+...+99.101
B=1.4+2.5+3.6+...+99.102
1.Tính:
A = 1.4+2.5+3.6+...+99.102A = 1(2+2)+2(3+2)+3(4+2)+...+99(100+2)
A = 1.2+1.2+2.3+2.2+3.4+3.2+...+99.100+99.2
A = (1.2+2.3+3.4+...+99.100)+2(1+2+3+...+99)
A = 333300 + 9900
A = 343200
Cho A = 1.4 + 2.5 + 3.6 + 4.7 + ... + 99.102 (Dấu chấm là dấu nhân)
Bạn zô đây nha: https://olm.vn/hoi-dap/question/839400.html
so so hang : (99.102-1.4):1.1+1=89.82
gia tri cua A : (99.102+1.4)x89.82:2= 4513.54482
mk đâu tien k cho mk nha
1.4+2.5+3.6+....+99.102
1.4+2.5+3.6+...+99.102=1(2+2)+2(3+2)+3(4+2)+...99(100+2)
=1.2+1.2+2.3+2.2+...+99.100+99.2
=(1.2+2.3+...+99.100)+2(1+2+...+99)
A=1.2+2.3+3.4+...+99.100(cho A la ten bieu thuc nay)
3A=1.2(3-0)+2.3(4-1)+...+99.100(101-98)
=(1.2.3+2.3.4+...+99.100.101)-(1.2.3+2.3.4+3.4.5+...+98.99.100
=99.100.101=>A=\(\frac{99.100.101}{3}\)=33330
2.(1+2+...99)
=2(100.99:2)=2.4950=9900
33330+9900=343200
vay...
D =1.4+2.5+3.6+.......+99.102
tính tổng nhanh nghe may ban
D =1.4+2.5+3.6+.......+99.102
D = 1. (2+2) +2.(2+3) +3.(2+4)+...+99.(100+2)
D = 1.2+1.2+2.2+2.3+2.3+3.4+...+2.99+99.100
D = (1.2+2.3+3.4+...+99.100) +2.(1+2+3+4+...+99)
*Gọi A= 1.2+2.3+3.4+...+99.100
3A = 3.(1.2+2.3+3.4+...+99.100)
3A = 1.2.3+2.3.3+...+99.100.3
3A = 1.2.3 +2 .3.(4-1)+...+99.100.(101-98)
3A = 1.2.3+2.3.4-1.2.3+...+ 99.100.101-98.99.100
3A = 99.100.101
3A = 3.33.100.101
A = 33.100.101
A = 333300
* Gọi B = 2. (1+2+3+4+...+99)
\__có 99 số hạng ___/
B= 2.[(1+99).99:2]
B = 2 .4950
B = 9900
A+B = 333300+9900 =343200
Vậy D =343200
tính nhanh
\(1.4+2.5+3.6+...+98.101+99.102\)
Ta có: A=1.4+2.5+3.6+.....+98.101+99.102
A=1.(2+2)+2.(3+2)+3(4+2)+........+98.(100+1)+99(100+2)
A=1.2+1.2+2.3+2.2+3.4+3.2+.........+98.100+98.1+99.100+99.2
A=(1.2+2.3+3.4+.......+99.100)+2.(1+2+3+4+......+99)
A=...................